U.S. patent application number 11/762026 was filed with the patent office on 2008-05-08 for joint assembly and related methods.
This patent application is currently assigned to Genie Industries, Inc.. Invention is credited to Gerard T. Perkins.
Application Number | 20080105498 11/762026 |
Document ID | / |
Family ID | 38832800 |
Filed Date | 2008-05-08 |
United States Patent
Application |
20080105498 |
Kind Code |
A1 |
Perkins; Gerard T. |
May 8, 2008 |
JOINT ASSEMBLY AND RELATED METHODS
Abstract
A structural member is provided in an embodiment for a lift
assembly. The structural member comprises an elongated member
having a pair of spaced apart sidewalls with a pair of aligned
apertures therein. A joint assembly comprises a support member is
positioned between the sidewalls and aligned with the apertures.
The support member has an outer dimension greater than the diameter
of the apertures so the support member will not pass through the
apertures. An interior sleeve is disposed adjacent to the support
member and extends through the apertures. The interior sleeve has
end portions projecting beyond the sidewalls. The end portions are
cold worked, radially flared portions adjacent to the sidewalls.
The radially flared portions have an outer diameter greater than
the diameter of the apertures. A portion of the sidewalls around
the apertures are fixedly captured between the radially flared
portion of the interior sleeve and the support member.
Inventors: |
Perkins; Gerard T.;
(Ashland, OH) |
Correspondence
Address: |
PERKINS COIE LLP;PATENT-SEA
P.O. BOX 1247
SEATTLE
WA
98111-1247
US
|
Assignee: |
Genie Industries, Inc.
Redmond
WA
|
Family ID: |
38832800 |
Appl. No.: |
11/762026 |
Filed: |
June 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60813300 |
Jun 12, 2006 |
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Current U.S.
Class: |
187/269 |
Current CPC
Class: |
B66F 11/042
20130101 |
Class at
Publication: |
187/269 |
International
Class: |
B66B 9/16 20060101
B66B009/16 |
Claims
1. A link arm assembly for use in a link set of a scissor lift
assembly, comprising: A link arm having a pair of sidewalls spaced
apart from each other, each of the sidewalls having a plurality of
apertures having a first diameter, each of the plurality of
apertures in one sidewall being axially aligned with another one of
the apertures in the other sidewall; and A joint assembly
comprising: A support sleeve positioned between the sidewalls and
aligned with a pair of the apertures in the sidewalls, the support
sleeve having an outer diameter greater than the first diameter of
the apertures; and An interior sleeve concentrically disposed
within the support sleeve, the interior sleeve having end portions
extending through the pair of apertures and projecting beyond the
sidewalls, the end portions having cold worked radially flared
portions adjacent to the sidewalls, the radially flared portions
having a diameter greater than the first diameter of the apertures,
and wherein a portion of the sidewalls around the aperture is
fixedly captured between the radially flared portion of the
interior sleeve and the support sleeve.
2. The link arm assembly of claim 1 wherein the link arm is a open
channel member with opposing sidewalls integrally connected to an
endwall.
3. The link arm assembly of claim 1 wherein the link arm is at
least one of a U-channel and a C-channel.
4. The link arm assembly of claim 1 wherein the link arm has at
least first and second pairs of axially aligned apertures, and
wherein the joint assembly is a first joint assembly disposed in a
first pair of the apertures, and further comprising a second joint
assembly disposed in the second pair of axially aligned
apertures.
5. The link arm assembly of claim 1 wherein the link arm is a pair
of flanged plates spaced apart from each other and with web
portions of the flanged plates defining the sidewalls and being
interconnect by the joint assemblies.
6. The link arm assembly of claim 1 wherein the link arm has a
boxed-beam cross section, and further comprising at least one
access aperture adjacent to at least one of the apertures.
7. The link arm assembly of claim 1 wherein the radially flared
portions of the interior sleeve are flared at approximately a
90-degree angle relative to a longitudinal axis of the interior
sleeve.
8. The link arm assembly of claim 1 wherein the radially flared
portions of the interior sleeve are flared at less than a 90-degree
angle relative to a longitudinal axis of the interior sleeve.
9. The link arm assembly of claim 1 wherein the radially flared
portions of the interior sleeve are flared at approximately a
45-degree angle relative to a longitudinal axis of the interior
sleeve.
10. The link arm assembly of claim 1 wherein the interior sleeve
has an inner surface that has been cold worked to a selected
surface condition during installation of the joint assembly.
11. The link arm assembly of claim 1 wherein interior sleeve has an
inner surface coated with a lubricious material that forms a
bearing surface.
12. The link arm assembly of claim 1, further comprising a pivot
pin disposed in the joint assembly and configured to pivotally
couple the link arm a second link arm.
13. The link arm assembly of claim 1 wherein the joint assembly
further comprising a spacer captured between the sidewall and the
radially flared portion.
14. The link arm assembly of claim 1 wherein the link arm is a
first link arm, and the joint assembly is a first joint assembly,
further comprising a second link arm configured substantially
identical to the first link arm and a second joint assembly
configured substantially identical to the first joint assembly,
wherein the first and second link arms are pivotally coupled
together by pivot member connected to the first and second joint
assemblies.
15. A scissor lift assembly, comprising: A plurality of link arms
pivotally coupled together to form an scissoring link set, each of
the link arm having a pair of sidewalls spaced apart from each
other, each of the sidewalls having a plurality of apertures having
a diameter, each of the plurality of apertures in one sidewall of a
link arm being axially aligned with another one of the apertures in
the other sidewall; and A plurality of joint assemblies attached to
the link arms, each joint assembly having an interior sleeve
extending through the pair of apertures and having end portions
projecting beyond the sidewalls, the end portions having cold
worked, radially flared portions adjacent to the sidewalls, the end
portions being in fixed engagement with portions of the sidewalls
around the apertures, the radially flared portions having a
diameter greater than the diameter of the apertures; and A pivot
member connected to adjacent joint assemblies of two adjacent link
arm and configured allow the two adjacent link arms to pivot
relative to each other at the joint assemblies and about the pivot
member.
16. A scissor lift assembly of claim 15, wherein each joint
assembly includes a support sleeve positioned between an aligned
pair of the apertures in the sidewalls of the link arm, the support
sleeve having an outer diameter greater than the diameter of the
apertures, and wherein a portion of the sidewalls around the
aperture is fixedly captured between the radially flared portion of
the interior sleeve and the support sleeve.
17. A scissor lift assembly of claim 15 wherein the link arms are
open channel members with opposing sidewalls integrally connected
to an endwall.
18. A scissor lift assembly of claim 15 wherein the link arms are
U-channels.
19. A scissor lift assembly of claim 15 wherein at least one of the
link arms includes a pair of flanged plates spaced apart from each
other and with web portions of the flanged plates defining the
sidewalls and being interconnect by the joint assemblies.
20. A scissor lift assembly of claim 15 wherein the radially flared
portions of the interior sleeve are flared at approximately a
90-degree angle relative to a longitudinal axis of the interior
sleeve.
21. A scissor lift assembly of claim 15 wherein the radially flared
portions of the interior sleeve are flared at approximately a
45-degree angle relative to a longitudinal axis of the interior
sleeve.
22. A scissor lift assembly of claim 15 wherein the interior sleeve
has an inner surface that has been cold worked to a selected
surface condition during installation of the joint assembly.
23. A scissor lift assembly of claim 15 wherein interior sleeve has
an inner surface coated with a lubricious material that forms a
bearing surface.
24. A structural member, comprising: An elongated member having a
pair of spaced apart sidewalls with a pair of aligned apertures
therein, the apertures having a diameter; and A joint assembly
comprising: A support member positioned between the sidewalls and
aligned with the apertures, the support member having an outer
dimension greater than the diameter of the apertures so the support
member will not pass through the apertures; and An interior sleeve
disposed adjacent to the support member and extending through the
apertures, the interior sleeve having end portions projecting
beyond the sidewalls, the end portions being cold worked, radially
flared portions adjacent to the sidewalls, the radially flared
portions having an outer diameter greater than the diameter of the
apertures, and wherein a portion of the sidewalls around the
apertures are fixedly captured between the radially flared portion
of the interior sleeve and the support member.
25. The structural member of claim 24 wherein the elongated member
is a open channel member.
26. The structural member of claim 24 wherein the elongated member
is a link arm of a link set for a scissor lift.
27. The structural member of claim 24 wherein the elongated member
comprises a pair of flanged plates spaced apart from each other and
with web portions of the flanged plates defining the sidewalls and
being interconnect by the joint assembly.
28. The structural member of claim 24 wherein the radially flared
portions of the interior sleeve are flared at approximately a
90-degree angle relative to a longitudinal axis of the interior
sleeve.
29. The structural member of claim 24 wherein the radially flared
portions of the interior sleeve are flared at less than a 90-degree
angle relative to a longitudinal axis of the interior sleeve.
30. The structural member of claim 24 wherein the structural member
is a sleeve concentrically disposed around the interior sleeve.
31. The structural member of claim 24 wherein the interior sleeve
has an inner surface that has been cold worked to a selected
surface condition during installation of the joint assembly.
32. A joint assembly, comprising: A first member having a first
aperture; A second member spaced apart from the first member and
having a second aperture axially aligned with the first aperture, A
support member positionable between the first and second members to
support at least a portion of the first and second members, the
support member being in alignment with the apertures, the support
member being sized so the support member will not pass through the
apertures; and An interior sleeve disposed adjacent to the support
member and extending between the first and second members and
through the first and second apertures, the interior sleeve having
end portions projecting beyond the first and second members, the
end portions being cold worked, radially flared portions adjacent
to the first and second members about the first and second
apertures, the radially flared portions having an outer diameter
greater than the diameter of the first and second apertures, and
wherein portions of the first and second member around the first
and second apertures are fixedly captured between the radially
flared portions of the interior sleeve and the support member.
33. The joint assembly of claim 32 wherein the first and second
members are sidewalls of a link arm.
34. The joint assembly of claim 32 wherein the first and second
members are flanged plates spaced apart from each other and with
web portions of the flanged plates defining the sidewalls and being
interconnect by the joint assembly.
35. A method of joining first and second member having apertures
therein, comprising: Securing the first and second members in a
spaced apart relationship with the apertures axially aligned with
each other; Placing a support member adjacent to the apertures and
between the first and second members and to block the first and
second members from moving toward each other past a selected
distance; Inserting an interior sleeve through the aligned
apertures in the first and second members, wherein unflared end
portions project away from the first and second members in opposite
directions; Radially flaring the end portions of the interior
sleeve by cold working the end portions; and Fixedly capturing
portions of the first and second members around the apertures
between the radially flared portions of the interior sleeve and the
support member to lock the joint assembly in place.
36. The method of claim 35 wherein the step of radially flaring the
end portions of the interior sleeve include plunging a flaring die
into the interior sleeve and causing the end portions to
plastically deform to the radially flared position.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present patent application is a non-provisional patent
application that claims priority to U.S. provisional Patent
Application No. 60/813,300, filed Jun. 12, 2006, which is
incorporated herein in its entirety by reference thereto.
TECHNICAL FIELD
[0002] The present invention is directed to joint assemblies for
pivoting and non-pivoting assemblies, and more particularly to
structural members and joint arrangements for pivoting and
non-pivoting assemblies.
BACKGROUND
[0003] Aspects of the prior art are described below and shown in
FIGS. 1-3 for purposes of background. FIG. 1 is a partially
exploded isometric view of a conventional scissor lift assembly 10
having a chassis 12 coupled to a platform 14 by a plurality of
scissoring link sets 16. Each link set 16 includes a pair of outer
link arms 18 pivotably attached to a pair of inner link arms 20.
The link arms are very strong steel, welded members having a
box-shaped cross-sectional shape, but the are heavy and expensive.
The outer link arms in a link set are pivotably attached to the
inner link arms of that link set at a midpoint that allows for the
scissoring action between the inner and outer link arms. The ends
of the inner link arms of a link set are pivotably connected to the
ends of outer link arms of the next higher or lower link set, or to
the platform or the chassis, depending upon the position of the
link set in the scissor lift assembly. The inner link arms are
connected to the outer link arms by a pivot pin 23 that extends
through welded, sometimes reinforced, joint portions 22 of the
respective link arms. The inner and outer link arms and the pivot
pins can be subjected to significant loads (e.g., axial and
torsional loads) and stresses during operation of the scissor lift
assembly.
[0004] FIG. 2 is an enlarged isometric view of an outer link arm 18
shown removed from a link set 16 of FIG. 1. FIG. 3 is an enlarged
cross-sectional view taken substantially along line 3-3 of FIG. 2,
with the joint portion 22 and link arm shown in solid lines and a
pivot pin 23 shown in phantom lines. The joint portions on the link
arm include a steel sleeve 24 that extends through a pair of holes
26 found in opposing sidewalls of the link arm. The steel sleeve is
welded to the link arm around one of the holes. The steel sleeve
also extends through the hole in the opposite sidewall and through
a steel reinforcement plate 28 welded to the sidewall generally
adjacent to the hole. The welded steel reinforcement plate provides
additional structure around the holes to help strengthen the link
arm at the joint portions and to help avoid stress cracks in the
welds through the operational life of the link arm and the joint
portion. The steel sleeve pivotally receives the pivot pin 23
(shown in phantom lines) so the link arm can pivot about the pivot
pin. Several link arms in a link set also often include welded
support plates or reinforced structures to which other assemblies
are securely connected. These plates and structures add to the
weight, cost and manufacturing process for each link set.
[0005] As shown in FIG. 3, the conventional steel sleeve 24 in the
reinforced joint portion 22 typically also includes bushings 30
mounted in counter bores 32 formed in the ends of the sleeve. The
bushings are positioned to engage the pivot pin 23 to provide for a
low friction interface with the pivot pin. Accordingly, the steel
sleeve must be machined and assembled with the bushings, thereby
adding to the overall cost of the assembled link arm, and thus, the
scissor lift assembly.
[0006] The welded construction of the steel link arm subjects the
link sets 16 of the scissor lift assembly 10 (FIG. 1) to internal
stresses that distort the shape and fit of the component parts,
which can damage the assembled bushings and create misalignment of
mated joint assemblies. This distortion and misalignment prevents
the scissors lift from raising and lowering smoothly, creating
stiff joints and jerky motion. Since the joints are not free
moving, greater force is required to effect movement, higher
hydraulic operating pressure is required, and components are
subjected to higher operating stress that manifests itself in
reduced working life and excessive energy consumption. The
resulting misalignment requires the use of highly resilient and
expensive bushings to attempt to compensate the welding and
fabrication processes. Additionally, the welded construction is
time consuming and labor intensive, while requiring high energy
input. The welded, steel, box-beam link arms result in a very heavy
link set that requires heavy duty motors, actuators, hydraulics,
and other components to reliably and smoothly operate the link set
over the life of the scissor-lift assembly, all of which increase
the cost and weight of the assembly. In addition, the heavy link
arms can be difficult or cumbersome to handle by personnel and
machines during the manufacturing process. The inventor has
recognized the need for improved joint assemblies that can easily,
quickly and securely interconnect members, such as structural
members, beams, or link arms used in lift assemblies to provide a
lighter weight, less expensive assemblies.
SUMMARY
[0007] The present invention provides a pivot joint assembly for a
pivoting structure that overcomes drawbacks of the prior art and
provides other benefits. One embodiment provides a link arm
assembly for use in a link set of a scissor lift assembly. The link
arm assembly comprises a link arm having a pair of sidewalls spaced
apart from each other. Each of the sidewalls has a plurality of
apertures with a first diameter. Each apertures in one sidewall is
axially aligned with another one of the apertures in the other
sidewall. A joint assembly comprises a support sleeve positioned
between the sidewalls and aligned with a pair of the apertures in
the sidewalls. The support sleeve has an outer diameter greater
than the first diameter of the apertures. An interior sleeve is
concentrically disposed within the support sleeve. The interior
sleeve has end portions extending through the pair of apertures and
projecting beyond the sidewalls. The end portions have cold worked,
radially flared portions adjacent to the sidewalls. The radially
flared portions have a diameter greater than the first diameter of
the apertures. A portion of the sidewalls around the aperture is
fixedly captured between the radially flared portion of the
interior sleeve and the support sleeve.
[0008] In another embodiment, a scissor lift assembly comprises a
plurality of link arms pivotally coupled together to form an
scissoring link set. Each link arm has a pair of sidewalls spaced
apart from each other. Each of the sidewalls has a plurality of
apertures. Each of the apertures in one sidewall of a link arm is
axially aligned with another one of the apertures in the other
sidewall. A plurality of joint assemblies is attached to the link
arms. Each joint assembly has an interior sleeve extending through
the pair of apertures and end portions projecting beyond the
sidewalls. The end portions have cold worked, radially flared
portions adjacent to the sidewalls. The end portions are in fixed
engagement with portions of the sidewalls around the apertures. The
radially flared portions have a diameter greater than the diameter
of the apertures. A pivot member is connected to adjacent joint
assemblies of two adjacent link arms and configured allow the two
adjacent link arms to pivot relative to each other at the joint
assemblies and about the pivot member.
[0009] In another embodiment, a structural member for a lift
assembly comprises an elongated member having a pair of spaced
apart sidewalls with a pair of aligned apertures therein. A joint
assembly comprises a support member is positioned between the
sidewalls and aligned with the apertures. The support member has an
outer dimension greater than the diameter of the apertures so the
support member will not pass through the apertures. An interior
sleeve is disposed adjacent to the support member and extends
through the apertures. The interior sleeve has end portions
projecting beyond the sidewalls. The end portions are cold worked,
radially flared portions adjacent to the sidewalls. The radially
flared portions have an outer diameter greater than the diameter of
the apertures. A portion of the sidewalls around the apertures are
fixedly captured between the radially flared portion of the
interior sleeve and the support member.
[0010] In another embodiment a joint assembly comprises a first
member having a first aperture, and a second member spaced apart
from the first member and having a second aperture axially aligned
with the first aperture. A support member is positionable between
the first and second members to support at least a portion of the
first and second members. The support member is in alignment with
the apertures. The support member is sized so the support member
will not pass through the apertures. An interior sleeve is disposed
adjacent to the support member and extends between the first and
second members and through the first and second apertures. The
interior sleeve has end portions projecting beyond the first and
second members. The end portions are cold worked, radially flared
portions adjacent to the first and second members about the first
and second apertures. The radially flared portions have an outer
diameter greater than the diameter of the first and second
apertures, and wherein portions of the first and second member
around the first and second apertures are fixedly captured between
the radially flared portions of the interior sleeve and the support
member.
[0011] In yet another embodiment, a method of joining first and
second member having apertures therein is provided. The method
comprises securing the first and second members in a spaced apart
relationship with the apertures axially aligned with each other. A
support member is placed adjacent to the apertures and between the
first and second members and to block the first and second members
from moving toward each other past a selected distance. An interior
sleeve is inserted through the aligned apertures in the first and
second members, wherein unflared end portions project away from the
first and second members in opposite directions. The end portions
of the interior sleeve are radially flared by cold working the end
portions. The first and second members around the apertures are
fixedly captured between the radially flared portions of the
interior sleeve and the support member to lock the joint assembly
in place.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a partially exploded isometric view of a prior art
scissor lift assembly with a plurality of link sets.
[0013] FIG. 2 is an enlarged isometric view of a prior art external
link member shown removed from one of the link sets of FIG. 1.
[0014] FIG. 3 is an enlarged cross-sectional view taken
substantially along line 3-3 of FIG. 2 showing the prior art link
arm and pivot joint portion.
[0015] FIG. 4 is an isometric view of a scissor lift assembly with
link sets having link arms and joint assemblies in accordance with
an embodiment of the present invention.
[0016] FIG. 5 is a bottom isometric view of a link arm shown
removed from the link sets of the scissor lift assembly of FIG. 4;
the link arm has three joint assemblies in accordance with an
embodiment of the present invention.
[0017] FIG. 6 is a partially exploded isometric view of the link
arm and joint assemblies of FIG. 5.
[0018] FIG. 7 is an enlarged cross-sectional view taken
substantially along line 7-7 of FIG. 5 showing one of the joint
assemblies.
[0019] FIG. 8 is an isometric view of a link arm and three joint
assemblies in accordance with another embodiment, wherein the link
arm has an access hole adjacent to at lease one of the joint
assemblies.
[0020] FIG. 9 is an isometric view of a link arm in accordance with
another embodiment, wherein the link arm has joint apertures that
receive joint members and access apertures adjacent to the joint
apertures.
[0021] FIG. 10 is a bottom isometric view of a link arm with joint
assemblies in accordance with another embodiment of the
invention.
[0022] FIG. 11 is an enlarged cross-sectional view taken
substantially along line 11-11 of FIG. 10 showing one of the joint
assemblies.
[0023] FIG. 12 is a bottom isometric view of a link arm with three
joint assemblies in accordance with another embodiment of the
invention.
[0024] FIG. 13 is an enlarged cross-sectional view taken
substantially along line 13-13 of FIG. 12 showing one of the joint
assemblies.
[0025] FIG. 14 is an enlarged cross-sectional view of a link arm
and a joint assembly in accordance with another embodiment of the
present invention.
[0026] FIG. 15 is an isometric view of a link arm with three joint
assemblies in accordance with another embodiment of the
invention.
[0027] FIG. 16 is an enlarged isometric view of an interior sleeve
of a joint assembly shown with flared ends and removed from the
link arm of FIG. 15.
[0028] FIG. 17 is an enlarged isometric view of a spacer shown
removed from the link arm of FIG. 15.
[0029] FIG. 18 is an isometric view of the link arm and the joint
assemblies with the interior sleeve shown in position relative to
the link arm and the spacer, with the ends of the interior sleeve
in a straight configuration before being flared radially outwardly
into engagement with the spacer.
[0030] FIG. 19 is an isometric view of a link arm and joint
assemblies in accordance with another embodiment, wherein the link
arm include a pair of spaced apart flanged plates rigidly connected
together by the joint assemblies.
[0031] FIG. 20 is an enlarged cross-sectional view taken
substantially along line 20-20 of FIG. 19.
[0032] FIGS. 21A-21C are schematic cross-sectional views
illustrating a joint forming method in accordance with an
embodiment of the present invention.
[0033] FIG. 22 is a schematic cross-sectional view of a first
flaring die positioned in a joint assembly during the formation of
the joint assembly in accordance with another embodiment of the
present invention.
[0034] FIG. 23 is a schematic cross-sectional view of a second
flaring die positioned in the joint assembly of FIG. 22 during the
formation of the joint assembly in accordance with an embodiment of
the present invention.
DETAILED DESCRIPTION
[0035] Embodiments of the present invention include structures with
improved joint assemblies, along with methods for making the joint
assemblies. Several specific details of the invention are set forth
in the following detailed description and in FIGS. 4-23 to provide
a thorough understanding of embodiments of the invention. The
embodiments are illustrated in the Figures and described below in
connection with a scissor lift assembly with link arms pivotably
coupled together by pivot joint assemblies One skilled in the art,
however, will understand that the present invention is applicable
to joining or forming other structural or non-structural members
with one or more joint assemblies for a fixed or movable
interconnections therebetween. Further, the present invention may
have additional embodiments, and that other embodiments of the
invention may be practiced without one or more of the specific
features described below. In other instances, well-known
structures, materials, or operations are not shown or described in
order to avoid obscuring aspects of the invention.
[0036] FIG. 4 is an isometric view of a scissor lift assembly 100
having link arms with joint assemblies pivotably coupled together
in accordance with an embodiment of the present invention. The
scissor lift assembly 100 includes a platform 102 coupled to a
chassis 104 by a plurality of link sets 106. The link sets are
formed by a plurality of link arms 108, including a pair of
interior link arms 108a and a pair of exterior link arms 108b
coupled together by joint assemblies 110 in the link arms and a
pivot pin 112 extending through adjacent joint assemblies. In the
illustrated embodiment, the interior and exterior link arms have
substantially the same construction.
[0037] FIG. 5 is a bottom isometric view of a link arm 108 shown
removed from the scissor lift assembly 100 of FIG. 4. The
illustrated link arm 108 has three joint assemblies 110 in
accordance with an embodiment of the present invention. FIG. 6 is a
partially exploded isometric view of the link arm 108 and joint
assemblies 110 of FIG. 5.
[0038] FIG. 7 is an enlarged cross-sectional view of the link arm
and joint assembly taken substantially along line 7-7 of FIG. 5. It
is to be understood that while the arm and joint assemblies are
described and shown herein in connection with link sets in a
scissor lift assembly, the arm structure and one or more joint
assemblies of the present invention can be used for other
assemblies.
[0039] As best seen in FIGS. 5 and 7, the illustrated link arm 108
is a U-shaped channel member having a pair of sidewalls 116
interconnected by an end wall 118. The channel has an open end 120
opposite the end wall so as to provide access into the interior
area 122 of the channel. In other embodiments, link arms 108 can
have other channel configurations, such as a C-channel or other
suitable open configuration. In yet other embodiments, the link arm
can be formed of a tubular member having a box construction or
other suitable closed configuration. The channel configuration of
the link arm provides a durable, open structure. The open end of
the channel also allows access into the interior area for ease of
manufacturing the link arm and pivot joint assembly (discussed in
greater detail below). The open end also allows for easy access to
the interior area for applying coatings, such as paint, a
corrosion-resistant coating, or other materials, within the link
arm. The interior area of the link arm could also be used as
storage space for components of the scissor lift assembly (FIG. 1)
or other assembly in which the link arm and joint assembly are
used.
[0040] As best seen in FIGS. 6 and 7, the sidewalls 116 of the link
arm 108 include a pair of axially aligned apertures 124 formed
therein. In the illustrated embodiment, the link arm includes three
sets of apertures 124 (see FIG. 6), including a set at each end of
the link arm and a set at the center portion of the link arm. Each
set of the apertures 124 receives a joint assembly 110.
[0041] The joint assembly 110 of the illustrated embodiment
includes an outer support sleeve 130 positioned in the interior
area 122 of the link arm 108 and coaxially aligned with a set of
the apertures 124 in the sidewalls 116. The support sleeve has a
length that approximates the distance between the sidewalls.
Accordingly, the support sleeve can be easily and quickly
positioned in the interior area through the link arm's open end 120
during assembly of the link arm and joint assembly. The support
sleeve has an outer diameter greater than the diameter of the
apertures in the sidewalls. In the illustrated embodiment, the
support sleeve has an inner diameter substantially equal to or
slightly larger than the diameter of the aperture. Accordingly, the
ends 132 of the support sleeve are immediately adjacent to the
portions of the sidewalls around the apertures.
[0042] The support sleeve 130 of the illustrated embodiment is made
from stock steel tube easily cut to size to fit snuggly between and
abut the sidewalls 116. Accordingly, the support sleeve acts as a
structural element that provides lateral support to the link arm
108. The support sleeve also blocks the sidewalls 116 of the
channel from deflecting toward each other. The support sleeve 130
also acts as a cross brace when the joint is assembled to help
maintain torsional rigidity to the link arm.
[0043] In other embodiments, a closed channel could be used for the
link arm 108. The support sleeves 130, if used, could be positioned
within the closed channel through an open end or other portion that
allows access into the interior area 122. As an example, FIG. 8 is
an isometric view of a link arm 108 and three joint assemblies 110
in accordance with another embodiment, wherein the link arm 108 has
an access hole 200 adjacent to at least one of the joint
assemblies. The access hole 200 provides access to the interior
area 122 of the link arm, so a person or machine can engage and
hold the support sleeve 130 in axial alignment with the apertures
124 during installation of the joint assembly 110.
[0044] FIG. 9 is an isometric view of a link arm 108 in accordance
with another embodiment, wherein the link arm has the apertures 124
that receive the joint assemblies 110 (FIG. 8). The link arm also
has access apertures 202 adjacent to the joint apertures. The link
arm 108 of the illustrated embodiment has a steel box-beam
construction with the axially aligned apertures 124 formed in the
sidewalls 116. In this embodiment, the access apertures 202 are
provided in the end wall 203, which extends between the sidewalls
116 above each of the joint apertures 124. The access aperture 202
provides access to the interior area 122 of the link arm 108, for
example, to allow a person or machine to temporarily hold the
support sleeve 130 (FIG. 8) in axial alignment with the joint
apertures 124. In other embodiments, the access holes 202 is shaped
and sized to allow a temporary support member to be placed in the
interior area 122 so as to span between and support the sidewalls
116 during assembly of the joint assembly (as discussed in greater
detail below). The temporary support can then be removed after the
joint assembly is installed.
[0045] As best seen in FIG. 7, the joint assembly 110 of the
illustrated embodiment also includes an interior sleeve 134 that
extends through the apertures 124 in the sidewalls 116 and through
the support sleeve 130. Accordingly, the support sleeve 130 and the
interior sleeve 134 are axially aligned and concentrically
oriented, although the interior sleeve is longer than the support
sleeve. The interior sleeve 134 of the illustrated embodiment has
an outer diameter that approximates the diameter of the apertures
124, so the interior sleeve can be easily yet snuggly inserted
through the aperture during the manufacturing process. The ends 136
of the interior sleeve 134 that extend beyond the sidewalls 116 are
flared radially outwardly and are positioned immediately adjacent
to the portions 133 of the sidewalls 116 around the aperture
124.
[0046] In the illustrated embodiment, each of the flared ends 136
is positioned such that the portion 133 of the sidewall 116 around
each aperture 124 is tightly held between the flared end of the
interior sleeve and the end 132 of the support sleeve 130. This
tight joint formed by the sidewall 116, the support sleeve 130, and
the interior sleeve 134 rigidly retains the components of the joint
assembly in a fixed position relative to the link arm 108 without
using any welds. The rigid connection of the support sleeve and the
interior sleeve with the sidewalls of the channel-shaped link arm
also adds axial and torsional stiffness of the link arm. In other
embodiments where additional torsional or axial stiffness may be
desired, additional stiffeners may be connected to the sidewalls
and/or provided within the interior area 122 of the link arm and
secured in place easily through access to the interior area through
the link arm's open end 120.
[0047] During a manufacturing process to assemble the link arm 108
and the joint assemblies 110, the interior sleeve 134 is a length
of straight tubing (prior to having the ends flared or otherwise
radially expanded), and the interior sleeve is positioned through a
set of the apertures 124 in the sidewalls 116 and through the
support sleeve 130. In the illustrated embodiment, the interior
sleeve 134 is a section of stock hydraulic tube cut to length,
although other suitable material can be used for the interior
sleeve in other embodiments. The ends 136 of the interior sleeve
are then flared, as discussed in greater detail below. Accordingly,
the ends 136 of the interior sleeve 134 in the illustrated
embodiment are cold-worked and radially expanded into rigid
engagement with the sidewall 116 of the link arm 108, thereby
providing the rigid interconnection between the link arm and the
joint assembly. It is noted that, while the manufacturing process
is discussed in connection with a joint assembly 110 for pivotal
interconnection of link arms, the joint assembly can be used for
joining two or more members in a fixed, non-moveable
orientation.
[0048] In the illustrated embodiment, the ends 136 of the interior
sleeve 134 are flared into approximately a 90.degree. angle. A
flared portion of the sleeve's end 136 abuts against the portion
133 of the sidewall 116 around the aperture 124, and that portion
of the sleeve's end is in direct alignment with the support sleeve.
Accordingly, when the interior sleeve 134 is cold worked, both ends
136 are flared simultaneously, and the support sleeve 130 reacts to
forces exerted against the sidewalls 116, thereby blocking the
sidewalls from flexing inwardly. While the illustrated embodiment
is discussed in connection with flaring the ends of the interior
sleeve, other cold-working techniques, such as cold heading,
staking, or other techniques, could be used for upsetting the ends
of the interior sleeve to provide a radially expanded portion with
a diameter greater than the diameter of the apertures 124 in the
sidewalls 116. Accordingly, the link arm 108 and the joint assembly
110 are assembled without welding any of the components. This
"weldless" construction is more efficient, less labor intensive,
and less expensive than the conventional welded construction of a
reinforced scissor link arm.
[0049] Referring again to FIG. 7, the interior sleeve 134 is shaped
and sized to pivotably receive the pivot pin 112 (shown in phantom
lines) therethrough. In the illustrated embodiment, the pivot pin
is retained in place and blocked from pulling back through the
interior sleeve by a snap ring 138 or other retention device
positioned within a groove 140 formed in the end portion 142 of the
pivot pin. The pivot pin has an outer diameter that approximates
the inner diameter of the interior sleeve 134 such that the joint
assembly and link arm can pivot about the pivot pin.
[0050] In one embodiment, the interior surface of the interior
sleeve 134 is formed by a layer of lubricious material adhered to
the body 150 of the interior sleeve to form a bearing surface 148.
The bearing surface 148 is configured to engage and slide against
an outer surface 152 of the pivot pin 112 without substantial
frictional losses. In the illustrated embodiment, the bearing
surface 148 is provided by coating the inside of the interior
sleeve with a lubricious material, such as an electroless nickel,
bronze, or non-metallic coating. The electroless nickel plating can
also be impregnated with a lubricious material. In one embodiment,
the electroless nickel plating is impregnated with Teflon.RTM.
(i.e., PTFE). In another embodiment, the pivot pin is provided with
a bearing surface coating that slideably engages the inside of the
interior sleeve. In yet another embodiment, both the pivot pin and
the interior sleeve can be provided with bearing surface coatings
that slideably engage each other.
[0051] The lubricious bearing surface coating is configured such
that additional bearings and/or bushings are unnecessary within the
interior sleeve 134 for engagement with the pivot pin 112. The
bearing surface coating can also provide corrosion protection in
the interior sleeve and/or on the pivot pin. Accordingly, the joint
assembly 110 of the illustrated embodiment is a bearingless
assembly, because additional bearing components or bushings are not
used between the interior sleeve and the pivot pin, while still
allowing for smooth, efficient, and effective rotational movement
of the link arm under working loads. However, discrete bearings or
bushings may be employed as well in other embodiments.
[0052] While the above embodiment uses a coating that is
impregnated or otherwise applied to the inside of the interior
sleeve 134 or to the outside of the pivot pin 112 or both, other
coating materials, impregnation processes, or other materials of
the joint assembly can be used to achieve the lubricious engagement
between the pivot pin and the interior sleeve. This configuration
can also allow for a reduced exterior size of the joint assembly
110, which may affect the size and/or amount of material needed in
the link arm 108 to operatively support the pivot joint assembly
and to withstand the operational loads on the link arm. In
addition, the joint assembly utilizes fewer parts, and the parts
can be made from stock components. The resulting weldless
manufacturing process is easier, faster, non-distorting, and less
expensive link arm and joint assembly that can be used in a scissor
lift assembly or other pivoting structure. The link arm and joint
assembly of the illustrated embodiment are also easier to maintain,
repair, or replace in the field, thereby decreasing the amount of
time the scissor lift assembly or other pivoting structure is out
of service.
[0053] The arrangement of the link arm 108 and joint assembly 110
can be used for both the interior link arm 108a and the exterior
link arm 108b of a link set 106 for a scissor lift assembly (FIG.
4). Washers, such as non-metallic low friction washers, and/or
other spacers can be provided between connected link arms (e.g., on
the pivot pins) as needed during assembly based upon the size and
overall configuration of the scissor lift assembly. In one
embodiment, the link arm and joint assemblies are provided for a
scissor lift assembly, and interior link arms 108a are spaced apart
from each other within a link set. The pivot pin 112 can be an
elongated pivot pin and a spacer (not shown) can be provided over
the pivot pin between the interior link arms to help maintain the
spacing of the interior link arms relative to each other during
assembly and operation of the link sets. Other spacing
configurations can be used for the interior and/or exterior link
arms in other embodiments.
[0054] FIG. 10 is a bottom isometric view of a link arm 108 and
joint assemblies 110 in accordance with another embodiment of the
invention. FIG. 11 is a cross-sectional view taken substantially
along line 11-11 of FIG. 10. In this embodiment, the link arm 108
is a U-channel, substantially as discussed above. The joint
assembly has the support sleeve 130 positioned within the interior
area 122 of the link arm substantially coaxially aligned with the
apertures 124 in the sidewalls 116, also as discussed above. In
this illustrated embodiment, the interior sleeve 134 extends
through the support sleeve 130 and the apertures 124 in the link
arm. The interior sleeve is radially expanded at its ends 136 to a
diameter greater than the diameter of the apertures. In the
illustrated embodiment, the ends 136 are radially expanded to
provide an angle relative to the adjacent sidewall 116 of less than
90.degree.. In the illustrated embodiment, the ends of the interior
sleeve are radially expanded to form an angle of approximately
45.degree. relative to the adjacent sidewall. The approximately
45.degree. angle provides a tight joint between the interior
sleeve, the support sleeve, and the sidewall around the apertures.
While the illustrated embodiment utilizes a 45.degree. angle, other
embodiments can be radially expanded to other angles relative to
the adjacent sidewall to provide the tight joint of the joint
assembly.
[0055] FIG. 12 is a bottom isometric view of a link arm 108 with
joint assemblies 110 in accordance with yet another embodiment.
FIG. 13 is an enlarged cross-sectional view taken substantially
along line 13-13 of FIG. 12, showing the joint assembly 110 in the
link arm. In the illustrated embodiment, the link arm is a U-shaped
channel substantially as discussed above. The support sleeve 130 is
axially aligned with the apertures in the sidewalls 116 and extends
between sidewalls as discussed above. The interior sleeve 134 is
positioned within the apertures 124 and extends through the support
sleeve, also as discussed above. In the illustrated embodiment, the
ends 136 of the interior sleeve are mechanically upset by staking
the ends to create a stepped arrangement at the ends. The stepped
structure at the end of the interior sleeve securely retains the
portion of the sidewall around the aperture against the end of the
support sleeve. Accordingly, the joint assembly is rigidly fixed to
the link arm without having to weld the components together.
[0056] FIG. 14 is a cross-sectional view of another embodiment
having the link arm 108, the support sleeve 130, and the interior
sleeve 134 substantially as discussed above. The ends 136 of the
support sleeve, however, have been cold-worked to radially expand
the ends to a diameter larger than the diameter of the apertures
124 to securely lock the support sleeve 130, the interior sleeve
134, and the portion of the sidewalls around the apertures in
place. In other embodiments, the ends of the interior sleeve can be
mechanically upset by other cold-working techniques or other
techniques to provide the radially enlarged end portions, thereby
providing the non-welded mechanical joint between the link arm, the
support sleeve, and the interior sleeve.
[0057] In yet other embodiments, the internal sleeve 134 can be
securely and rigidly retained in place in the link arm 108 by other
non-welded, mechanical locking mechanisms without having to
physically expand the ends 136 of the interior sleeve. For example,
the pivot pin can be provided with two annular grooves positioned
to be adjacent to each end of the internal sleeve and/or adjacent
to the sidewalls of the link arm. Snap rings can be releasably
locked to the pivot pin in the annular grooves so as to abut the
internal sleeve. If the internal sleeve's length is equal to or
less than the width of the link arm, then the snap rings will abut
the sidewalls of the link arm. Other non-welded, mechanical locking
means can be used in other embodiments. For example, the ends of
the interior sleeve can be provided with grooves positioned to be
adjacent to the sidewalls. Snap rings or other mechanical locking
mechanisms can be attached to the interior sleeve to lock the
sleeve in position to create a substantially rigid joint relative
to the sidewalls. In these alternate embodiments that do not flare
the ends of the interior sleeve, tolerances of the interior sleeve,
the width of the link arm, the distance between the sidewalls, and
the mechanical connectors are selected to achieve the tight joint
between the components.
[0058] FIG. 15 is an isometric view of a link arm 160 with three
joint assemblies 162 in accordance with another embodiment of the
invention. The illustrated link arm is a tubular member having a
rectangular or square cross-sectional shape, although other
embodiments can use a link arm having a channel configuration as
discussed above or other tubular shapes. The link arm has opposing
sidewalls 164 with an opposing set of apertures 166 in the
sidewalls for each joint assembly. The joint assembly includes a
sleeve 168 that extends through a set of the opposing apertures. As
best seen in FIG. 16, the ends 170 of the sleeve 168 (which are
shown removed from the joint assembly) are flared radially
outwardly and have a diameter greater than the diameter of the
apertures (FIG. 13). Referring again to FIG. 15, the joint assembly
also includes at least one spacer 172 securely sandwiched between
the flared end 170 of the sleeve and the sidewall of the link arm.
In the illustrated embodiment, each joint assembly includes two
spacers positioned on opposite sides of the link arm. The sleeve
extends through holes 174 in the spacers, and each flared end of
the sleeve securely holds a spacer against the adjacent sidewall of
the link arm. This spacer also serves to add rigidity to the
section.
[0059] As best seen in FIG. 16, the sleeve 168 is configured to
receive a pivot pin 112 (shown in phantom lines) therethrough such
that the link arm can pivot about the pivot pin. The sleeve 168 can
have an interior surface defined by a lubricious material adhered
to the body 176 of the sleeve to form a bearing surface 178,
discussed above. In another embodiment, the pivot pin has the
lubricious bearing surface as discussed above that engages the
interior of the sleeve. In another embodiment, both the sleeve and
the pivot pin have lubricious bearing surfaces that engage each
other and allow for pivotal motion of the link arm about the pivot
pin with low frictional losses.
[0060] FIG. 17 is an enlarged isometric view of one of the spacers
172 shown removed from the link arm of FIG. 15. FIG. 18 is an
isometric view of the link arm 160 and the joint assemblies 162
with the sleeve 168 shown in position relative to the link arm and
the spacer 172. The ends 170 of the sleeve 168 are shown in FIG. 18
in a straight configuration before being flared radially outwardly
into engagement with the spacer. The spacer 172 in the illustrated
embodiment is a ring with an outer diameter greater than the
diameter of the apertures 166 in the link arm 160 (FIG. 17). The
spacer 172 has a hole 175 therethrough with a diameter slightly
larger than the outer diameter of the non-flared portion 179 of the
sleeve (FIG. 18). Accordingly, the spacer can be positioned over
the sleeve 168 and adjacent to the sidewall 164 of the link arm
before the end of the sleeve is flared or otherwise radially
expanded.
[0061] The spacer 172 in the illustrated embodiment has a contoured
recess 180 around the hole 175. The recess is shaped to
substantially correspond to the shape of the end 170 of the sleeve
168 when flared. Accordingly, when the ends of the sleeve are
flared via cold working the sleeve, the flared ends mate with the
contoured recess and rigidly fix the spacer against the sidewall of
the link arm without any welding of the components.
[0062] The joint assembly 162 of the illustrated embodiment does
not include a support sleeve within the link arm's interior area.
In other embodiments, the joint assembly 162 can include the
support sleeve within the interior area of the link arm and
concentrically disposed around the interior sleeve 168. In yet
other embodiments, the pivot pin can be retained by other
non-welded, mechanical locking means as discussed above. The spacer
can include a recess shaped to receive at least a portion of the
mechanical locking means (e.g., a snap ring or other locking
device).
[0063] The link arms 108 and joint assembly 110 as discussed above
can be used for the interior or exterior link arms, thereby
providing commonality of components for use in an assembly such as
a link set for a scissor lift assembly. Accordingly, the numbers of
unique parts required to build the assembly is reduced, thereby
decreasing the costs of the manufacturing process. In addition, the
link arm and the joint assembly are manufactured without welding,
so the manufacturing process is less costly and less time
consuming. The link arm and joint assemblies also avoid the
drawbacks of distortion or warping that can occur with welding of
components. The link arm and joint assemblies may also be lighter
in weight than conventional welded link arms without a reduction of
operational strength. Accordingly, the link sets formed by the link
arms with the joint assemblies and used in a scissor lift assembly
are more free moving and easier to build than conventional link
sets, which translate into an assembly that costs less to
manufacture while maintaining the required strength and
durability.
[0064] FIG. 19 is an isometric view of a structure, such as a link
arm assembly 300 and with three joint assemblies 302 in accordance
with another embodiment. FIG. 20 is an enlarged cross-sectional
view of the link arm assembly 300 taken substantially along lines
20-20 of FIG. 19. The link arm assembly 300 of the illustrated
embodiment includes a pair of spaced apart plates 304 rigidly
connected together by the joint assemblies 302. The plates 304 are
elongated flanged plates having a web portion 306 extending between
a pair of angled flanged portions 308. The flanged portions 308
strengthen and stiffen the plates 304 in bending and in
torsion.
[0065] Each flanged plate 304 has a plurality of joint apertures
310 therein that receive the joint assemblies 302. In the
illustrated embodiment, the flanged plates 304 are configured to be
positioned adjacent to each other with the apertures 310 in one
plate 304 axially aligned with the apertures in the other plate.
Each joint assembly 302 is disposed in the pair of align apertures
310 and securely engaged the portion 307 of the web 306 around the
apertures. Accordingly, the joint assemblies 302 rigidly and
securely hold the flanged plates together in a fixed spaced apart,
substantially parallel arrangement. Accordingly, the flanged plates
308 and the joint assemblies form a rigid assembly that can be used
as a link arm, a beam, a boom arm, or other rigid, lightweight,
inexpensive structural member.
[0066] As best seen in a FIG. 20, the joint assembly 302 of the
illustrated embodiment has a similar construction to the joint
assembly described above. The joint assembly 302 has a support
sleeve 312 extending between the web 306 of the plates 304. The
support sleeve 312 has an outer diameter larger than the diameter
of the apertures 310 in the web. Accordingly, the support sleeve
312 holds the two flanged plates 304 apart from each other. The
inner sleeve 314 is disposed within the support sleeve 312 and
extends through the apertures 310 in the plates 304. The ends 316
of the inner sleeve 314 are radially flared, as described in
greater detail below, so the portion 307 of the web 306 around the
respective aperture 310 is rigidly fixed between the ends 311 of
the support sleeve 312 and the flared ends 316 of the inner sleeve
314. This rigid interconnection provides a very strong, non-welded
joint that joins the flanged plates together. This joint assembly
302 can be used as part of a pivot joint arrangement, such as
between two link arm assemblies, wherein a pivot pin can be
positioned through a pair of the aligned joint assemblies, as
discussed above. In other embodiments, the joint assembly 302 can
be a stand-alone joint that securely joins two or more plates or
other structures together in a weld-free arrangement.
[0067] FIGS. 21A-21C are schematic cross-sectional views
illustrating the method of forming a joint assembly 110 in
accordance with an embodiment of the present invention. The method
is discussed in connection with forming a joint assembly 110 in a
structural member, such as a link arm 108, although it is to be
understood that the method is also applicable to forming a joint
assembly in another structure. As an example, the method can be
used to form one or more joint assemblies that join two or more
independent structures together.
[0068] In the illustrated embodiment, the link arm 108 includes a
pair of axially aligned apertures 124 in the sidewalls 116. The
apertures of the illustrated embodiment are co-axially aligned with
a joint axis substantially perpendicular to the longitudinal axis
of the link arm In other embodiments, however, the aperatures 124
and the joint assembly can be configured along an axis skewed angle
(e.g., non-perpendicular) relative to the longitudinal axis of the
link arm.
[0069] When the joint assembly 110 is to be installed, the link arm
108 is securely held in a fixed position, such as by a jig, clamp,
or other suitable fixture. The joint assembly 110 is formed by
positioning the support sleeve 130 between the sidewalls 116 in
axial alignment with the apertures 124. As discussed above, the
support sleeve 130 is sized so it does not extend through the
apertures 124, and it supports the portions of the sidewalls 116
around the apertures 124. Accordingly, the support sleeve blocks
the sidewalls from overly deflecting or deforming under compression
loads.
[0070] While the support sleeve 130 of the illustrated embodiment
is a cylindrical sleeve, other embodiments can use non-cylindrical
sleeves between the sidewalls 116. In yet other embodiments, other
support structures can be positioned between the sidewalls 116 to
support the sidewalls under compression loads used to form the
joint assembly, discussed in greater detail below. These support
structures can remain with the link arm as part of the finished
joint assembly. In other embodiments, the support structures can be
removable members that are temporarily placed between the sidewalls
116 during formation of the joint assembly, and then removed after
the joint assembly is formed.
[0071] Referring again to FIG. 21A, after the support sleeve 130 is
positioned between the apertures 124, the interior sleeve 134 is
inserted through the apertures 124 and into the support sleeve 130
so that the ends 136 of the interior sleeve project outwardly from
both sidewalls. In this position, the interior sleeve has an outer
diameter that approximates the diameter of the apertures, so the
interior sleeve can easily slide through the apertures 120 and the
support sleeve, before the ends 136 are flared. In one embodiment,
the interior sleeve 134 is positioned so that approximately equally
sized end portions project away from the sidewalls 116. In other
embodiments, the interior sleeve 134 can be positions so that
different lengths of the interior sleeve project from the opposing
sidewalls 116.
[0072] After the interior sleeve 134 is in position, first flaring
dies 350 are inserted from opposite directions into the open ends
136 of the interior sleeve during a plunging stroke. Each first
flaring die 350 has a leading portion 352 sized to fit into the
interior sleeve. The first flaring die also has a body portion 354
with flaring section 356 and a mounting section 357. In the
illustrated embodiment, the flaring section 356 has a partially
conical surface configured at approximately 45-degrees relative to
the longitudinal axis of the interior sleeve. The mounting section
357 of the body portion 354 is configured to be engaged by a press
assembly or other tool that moves the first flaring die into and
out of engagement with the interior sleeve. The press assembly or
other tool securely retains the first flaring dies 350 in axial
alignment with each other and in axial alignment with the interior
sleeve 134. The press assembly is configured to simultaneously
axially plunge the first flaring dies 350 toward each other at
substantially the same rate during the flaring stroke. During the
flaring stroke of the illustrated embodiment, the first flaring
dies 350 are not rotating relative to the interior sleeve. The
press assembly also moves the flaring dies 350 away from each other
and out of the interior sleeve 134 during a removal stroke.
[0073] In one embodiment, the press assembly begins to move the
first flaring dies 350 along the flaring stroke, and the leading
portions 352 of each die are simultaneously pressed into the
interior sleeve 134. As the flaring stroke continues, the press
assembly simultaneously presses the 45-degree flaring sections 356
into the ends 136 of the interior sleeve 136 with sufficient force
to plastically deform the ends of the interior sleeve to match the
45-degree angle of the flaring section. As discussed above, the
support sleeve 130 surrounding the interior sleeve blocks the
sidewalls 116 from substantially deforming under any compression
loads exerted on the sidewalls as the flaring dies plunge into and
flare the ends of the interior sleeve.
[0074] In the illustrated embodiment, the interior sleeve 134 is a
steel or other metal tube having a modulus of elasticity such that
the ends 136 of the sleeve will undergo the plastic deformation
during the flaring stroke without the ends splitting or cracking.
Although the first flaring die of the illustrated embodiment has a
45 degree flare, other embodiments can use one or more flaring dies
configured to provide a different degree of flare.
[0075] At the end of the flaring stroke, the leading portions 352
of the first flaring dies 350 are adjacent to each other within the
interior sleeve 134. The press assembly then reverses and the first
flaring dies 350 are moved through the removal stroke, wherein the
first flaring dies are axially removed from the interior sleeve.
Because both ends 136 of the interior sleeve 134 are simultaneously
flared during the flaring stroke of the illustrated embodiment, the
interior sleeve can not be pulled out of the apertures 124 during
the removal stroke.
[0076] In one embodiment, the leading portion 352 of the first
flaring die 350 has an outer diameter slightly greater than the
inner diameter of the interior sleeve 134. The leading portion 352
also has a tapered free end 360 that tapers radially inwardly to an
outer diameter less than the inner diameter of the interior sleeve
134. As the flaring dies 350 begin their flaring strokes, the
tapered free ends 360 are first pressed into the open ends 136 of
the interior sleeve 134 without deforming the interior sleeve.
[0077] As the first flaring dies 350 continue along the flaring
stroke, the rest of the leading portions 352 are pressed into the
interior sleeve, and the larger outer diameter of the leading
portion causes portions of the interior sleeve between the
apertures to radially expand. The leading portion 352 of each
flaring die 350 can be sized to cause plastic deformation of the
interior sleeve 134 as the flaring die moves along its flaring
stroke, thereby quickly and accurately sizing the inner diameter of
the interior sleeve during the flaring stroke.
[0078] As best seen in FIG. 21B, the flaring method of the
illustrated embodiment includes flaring the ends of the interior
sleeve to an approximately 90-degree angle relative to the
longitudinal axis of the interior sleeve. In the illustrated
embodiment, the ends 136 of the interior sleeve 134 are flared to
the 90-degree orientation after the ends have been flared to the
45-degree angle by the first flaring dyes 350, as discussed above.
This second flaring step includes simultaneously pressing a pair of
second flaring dies 370 into the interior sleeve 134 in a manner
similar to pressing the first flaring dies 350 into the interior
sleeve discussed above.
[0079] Each second flaring die 370 has a leading portion 372 that
fits into the interior sleeve, and a body portion 374 with flaring
section 376 and a mounting section 377. In the illustrated
embodiment, the flaring section 376 of second flaring die 370 has a
substantially flat annular shoulder 378 oriented at approximately
90-degrees relative to the longitudinal axis of the inner sleeve
134. The mounting section 377 of the body portion 374 is coupled to
the press assembly or other tool as discussed above. The press
assembly or other tool securely holds the second flaring dies 370
in axial alignment with each other and in axial alignment with the
interior sleeve 134. The press assembly simultaneously moves the
second flaring dies 370 toward each other at substantially the same
rate during the flaring stroke and away from each other during the
removal stroke.
[0080] In one embodiment, the press assembly begins to move the
second flaring dies 370 along the flaring stroke, and the leading
portions 372 of each die are simultaneously pressed into the
interior sleeve 134. As the flaring stroke continues, the press
assembly simultaneously presses the flat annular shoulder 378
against the 45-degree flared ends 136 of the interior sleeve 136,
thereby further flaring the ends 136 radially outwardly.
[0081] At the end of the flaring stroke, the leading portions 372
of the second flaring dies 370 are adjacent to each other within
the interior sleeve 134. The flat annular shoulder 378 of the
flaring sections 376 is immediately adjacent to the sidewalls 116,
whereby the flared ends 136 of the interior sleeve 136 is oriented
at a 90-degree angle and positioned immediately adjacent to the
sidewalls 116. Although the second flaring die 370 of the
illustrated embodiment has a 90 degree flare, other embodiments can
use one or more flaring dies configured to provide a different
degree of flare.
[0082] Upon completion of the flaring stroke, the press assembly
reverses and the second flaring dies 370 are moved through the
removal stroke, wherein the second flaring dies are removed from
the interior sleeve 134. Accordingly, the interior sleeve 134 and
the support sleeve 130 are securely fixed in place in the apertures
124 in the link arms without requiring any welding.
[0083] In one embodiment, the leading portion 372 of the second
flaring die 370 can also have a tapered free end 380 that tapers
from an outer diameter slightly greater than the inner diameter of
the interior sleeve 134, similar to the first flaring die 350
discussed above. Accordingly, as the second flaring dies 370 move
through the flaring stroke, the leading portion 372 causes the
interior sleeve to slightly radially expand, thereby simultaneously
sizing and conditioning the inner surface of the interior sleeve.
While the above embodiment is described with the leading portions
352 and 372 of the first and second flaring dies configured to
radially expand the inner surface of the interior sleeve between
the apertures, other embodiments can be configured so that the
leading portions 352 and 372 of only the first or second flaring
dies 350 or 370 will radially expand the portion of the interior
sleeve between the apertures. In other embodiments, the leading
portions 352 and 372 of the first and second flaring dies 350 and
370 can be configured so the leading portions do not plastically
deform the portion of the interior sleeve between the
apertures.
[0084] When the pair of first and/or second flaring dies 350/370
radially expands the interior sleeve 134 between the apertures, a
middle portion 388 of the interior sleeve that is adjacent to the
tapered free ends of the flaring dies 350/370 will not be radially
flared. Accordingly, the interior of the sleeve may have an annular
bump 389 therein. In one embodiment illustrated in FIG. 21C, a
plunging die 390 can be pressed through the interior sleeve 134
from either end to smooth out the annular bump 389.
[0085] In the illustrated embodiment, the 390 plunging die has an
elongate plunging portion 392 with an outer diameter substantially
identical to or slightly larger than the outer diameter of the
leading portions 352/372 of the first and/or second flaring dyes
350/370. The plunging portion 392 is moved through a plunging
stroke so as to radially expand at least the middle portion of the
interior sleeve's inner surface. The plunging portion is then
removed from the interior sleeve during a removal stroke. As a
result, the inner surface of the interior sleeve is cold worked to
provide the desired inner diameter and surface condition without
having to ream, drill or otherwise remove material from the inner
sleeve.
[0086] While the above embodiments flare both ends 136 of the
interior sleeve 134 simultaneously, other embodiments can flare one
end of the interior sleeve at a time. FIG. 22 is a schematic
cross-sectional view of a first flaring die 400 positioned in a
joint assembly 110 during an intermediate step of flaring one end
136 of the interior sleeve 134. In this embodiment, after the
support sleeve 130 is positioned between the sidewalls 116 and the
apertures 124 as discussed above, the interior sleeve 134 is
inserted through the apertures 124 and the support sleeve 130, so
the ends 136 of the interior sleeve project outwardly from the
sidewalls. One end of the interior sleeve 134 is temporarily
positioned in or adjacent to a spacer 402 that engages the sidewall
116. In the illustrated embodiment, the spacer 402 is an annular
ring that temporarily receives a free end of the interior sleeve
134 during the flaring process. The spacer 402 helps maintain the
axial position of the interior sleeve 134 relative to the link arm
108 or other structure while the other end 136 of the interior
sleeve 134 opposite the spacer is flared.
[0087] After the interior sleeve 134 is in position, the first
flaring die 400 is plunged into the open end 136 of the interior
sleeve opposite the spacer 402. The flaring die 400 has a leading
portion 404 that fits into the interior sleeve. The flaring die 400
also has a flaring section 408 and a mounting section 410, similar
to the first flaring die 350 discussed above. In the illustrated
embodiment, the flaring section 408 provides a 45-degree flare,
although the flaring section can be configured to provide a
different flare angle. The mounting section 410 is also configured
to be coupled to a press assembly or other tool that moves to
flaring die into and out of engagement with the interior sleeve, as
discussed above.
[0088] The press assembly securely retains the first flaring die
400 in axial alignment with the interior sleeve 134 and presses the
flaring section 408 along a flaring stroke into the end of the
interior sleeve, thereby plastically deforming and radially
expanding the end of the interior sleeve to approximately a
45-degree angle. The first flaring die 400 also can be configured
to radially expand the inner surface of the interior sleeve, as
discussed above. The first flaring die is then moved along a
removal stroke and removed from the interior sleeve as discussed
above.
[0089] As best seen in FIG. 23, a second flaring die 420 can then
be used to flare the end 136 of the interior sleeve 134 to the
approximately 90-degree angle while the opposite end of the
interior sleeve remains unflared and adjacent to the spacer 402.
The second flaring die 420 also has a leading portion 422 that fits
into the interior sleeve, a flaring section 426 that flares end of
the interior sleeve, and an mounting section 427 couplable to the
press assembly. In the illustrated embodiment, the flaring section
426 of second flaring die 420 has a substantially flat annular
shoulder 428 configured at approximately 90-degrees relative to the
longitudinal axis of the inner sleeve 134, substantially similar to
the second flaring die 370 discussed above. In one embodiment, the
press assembly presses the flat annular shoulder 428 against the
45-degree flared end 136 of the interior sleeve 136, thereby
flaring the end radially outwardly to a 90-degree angle. Although
the second flaring die 420 of the illustrated embodiment provides
has a 90 degree flare, other embodiments can use one or more
flaring dies configured to provide a different degree of flare. In
addition, the second flaring die 420 can be configured in at least
one embodiment to radially expand the inner surface of the interior
sleeve, as discussed above. In another embodiment, the second
flaring die 420 is configured to extend into the interior sleeve
without radially expanding the inner surface as discussed
above.
[0090] Upon completion of the flaring stroke, the second flaring
die 420 is reversed and moved through the removal stroke, wherein
the second flaring die is removed from the interior sleeve 134.
After the first end 136 of the interior sleeve 134 has been flared,
the first and second flaring dies can be used to flare the other
end of the interior sleeve, in substantially the same manner as
discussed above. When flaring this second end of the interior
sleeve, however, the spacer ring is not needed. A plunger die can
then be passed through the interior sleeve as discussed above, as
needed to cold work and condition the inner surface of the interior
sleeve between the apertures 124.
[0091] The resulting joint assembly in a link arm, structural
member, or other members provides a very strong, rigid joint to
support a pivot arrangement or to fix two components together. The
joint is weldless and it is substantially less labor intensive and
less expensive than conventional welded joints. The joint assembly
works with the structural member(s), so that fewer parts are
needed, resulting in a lighter weight assembly without sacrificing
strength or performance. In addition, the amount of time and
man-power needed for manufacturing is substantially reduced, at
least in part because the assembly is not welded.
[0092] From the foregoing, it will be appreciated that specific
embodiments of the invention have been described herein for
purposes of illustration, but that various modifications may be
made without deviating from the spirit and scope of the invention.
Accordingly, the invention is not limited except as by the appended
claims.
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